2021 LEXUS RC350 engine

3157-2. Steps to take in an emergency
7
When trouble arises
The engine starting system may be
malfunctioning due to an electrical
problem such as electronic key battery
depletion or a blown fuse. However, an
interim measure is available to start the
engine. (P.315)
One of the following may be the cause
of the problem:
 One or both of the battery terminals
may be disconnected. ( P.263)
 The battery may be discharged.
( P.319)
 There may be a malfunction in the
steering lock system.
Contact your Lexus dealer if the problem
cannot be repaired, or if repair procedures
are unknown.
When the engine does not start, the
following steps can be used as an
interim measure to start the engine if
the engine switch is functioning nor-
mally:
1 Set the parking brake.
2 Shift the shift lever to P.
3 Turn the engine switch to ACCES-
SORY mode. 4
Press and hold the engine switch
for about 15 seconds while
depressing the brake pedal firmly.
Even if the engine can be started using
the above steps, the system may be
malfunctioning. Have the vehicle
inspected by your Lexus dealer.
The starter motor does not turn
over
The starter motor does not turn
over, the interior lights and head-
lights do not turn on, or the horn
does not sound.
Emergency start function

3177-2. Steps to take in an emergency
7
When trouble arises
■When the electronic key does not work
properly
●Make sure that the smart access system
with push-button start has not been deac-
tivated in the customization setting. If it is
off, turn the function on.
●Check if battery-saving mode is set. If it is
set, cancel the function. ( P.96)
■Unlocking the door
Use the mechanical key ( P.84) in
order to perform the following opera-
tions: 1
Insert the mechanical key while
pulling on the driver’s door handle.
2 Unlocking the door.
3 Remove the key, return the handle,
and then pull the handle again.
■Locking the door
1 Move the inside lock button to the
lock position.
2 Close the door.
■Opening the trunk
Turn the mechanical key clockwise to
open. ( P.57)
If the electronic key does not
operate properly
If communication between the
electronic key and vehicle is inter-
rupted ( P.96) or the electronic
key cannot be used because the
battery is depleted, the smart
access system with push-button
start and wireless remote control
cannot be used. In such cases, the
doors and trunk can be opened and
the engine can be started by follow-
ing the procedure below.
NOTICE
■In case of a smart access system with
push-button start malfunction or
other key-related problems
Take your vehicle with all the electronic
keys provided with your vehicle, includ-
ing the card key, to your Lexus dealer.
Locking and unlocking the doors
and opening the trunk

3187-2. Steps to take in an emergency
■Key linked functions
1 Locks both side door
2 Closes the windows and moon roof (if
equipped) (turn and hold)
*
3Unlocks the door
Turning the key rearward unlocks the
driver’s door. Turning the key again unlocks
the other door.
4 Opens the windows and moon roof (if
equipped) (turn and hold)
*
*
: These settings must be customized at
your Lexus dealer.
1 Ensure that the shift lever is in P and
depress the brake pedal.
2 Touch the Lexus emblem side of the
electronic key to the engine switch.
When the electronic key is detected, a
buzzer sounds and the engine switch will
turn to IGNITION ON mode.
When the smart access system with
push-button start is deactivated in custom-
ization setting, the engine switch will turn
to ACCESSORY mode.
3 Firmly depress the brake pedal and
check that is shown on the
multi-information display.
4 Press the engine switch.
In the event that the engine still cannot
be started, contact your Lexus dealer.
■Stopping the engine
Shift the shift lever to P and press the engine
switch as you normally do when stopping
the engine.
■Electronic key battery
As the above procedure is a temporary
measure, it is recommended that the elec-
tronic key battery be replaced immediately
when the battery is depleted. ( P.277)
■Alarm (For Canada)
Using the mechanical ke y to lock the doors
will not set the alarm system.
If a door is unlocked using the mechanical
WARNING
■When using the mechanical key and
operating the power windows or
moon roof
Operate the power window or moon
roof after checking to make sure that
there is no possibilit y of any passenger
having any of their body parts caught in
the window or moon roof.
Also, do not allow ch ildren to operate the
mechanical key. It is possible for children
and other passengers to get caught in
the power window or moon roof.
Starting the engine

3197-2. Steps to take in an emergency
7
When trouble arises
key when the alarm system is set, the alarm
may be triggered.
■Changing engine switch modes
Release the brake pedal and press the
engine switch in step 3 above.
The engine does not start and modes will be
changed each time the switch is pressed.
(  P.129)
If you have a set of jumper (or booster)
cables and a second vehicle with a
12-volt battery, you can jump start your
vehicle by following the steps below.
1 Confirm that the electronic key is
being carried.
When connecting the jumper (or booster)
cables, depending on the situation, the
alarm may activate and doors locked.
( P.58)
2 Open the hood. ( P.255)
3 Connect a positive jumper cable clamp to on your vehicle and connect the
clamp on the other end of the positive cab le to on the second vehicle. Then,
connect a negative cable clamp to on the second vehicle and connect the
clamp at the other end of the negative cable to .
 RC350/RC300 AWD
If the vehicle battery is dis-
charged
The following procedures may be
used to start the engine if the vehi-
cle’s battery is discharged.
You can also call your Lexus dealer
or a qualified repair shop.
Restarting the engine
A
B
C
D

3207-2. Steps to take in an emergency
Positive (+) battery terminal (your vehicle)
Positive (+) battery terminal (second vehicle)
Negative (-) battery terminal (second vehicle)
Solid, stationary, unpainted metallic point away from the battery and any mov-
ing parts as shown in the illustration
 RC300
Positive (+) battery terminal (your vehicle)
Positive (+) battery terminal (second vehicle)
Negative (-) battery terminal (second vehicle)
Solid, stationary, unpainted metallic poin t away from the battery and any mov-
ing parts as shown in the illustration
4 Start the engine of the second vehi-
cle. Increase the engine speed
slightly and maintain at that level for
approximately 5 minutes to
recharge the battery of your vehi-
cle.
5 Open and close any of the door of
your vehicle with the engine switch
off. 6
Maintain the engine speed of the
second vehicle and start the engine
of your vehicle by turning the
engine switch to IGNITION ON
mode.
7 Once the vehicle’s engine has
started, remove the jumper cables
in the exact reverse order from
which they were connected.A
B
C
D
A
B
C
D

3217-2. Steps to take in an emergency
7
When trouble arises
Once the engine starts, have the vehi-
cle inspected at your Lexus dealer as
soon as possible.
■Starting the engine when the battery is
discharged
The engine cannot be started by push-start-
ing.
■To prevent battery discharge
●Turn off the headlights and the audio sys-
tem while the engine is off.
●Turn off any unnecessary electrical com-
ponents when the vehicle is running at a
low speed for an extended period, such
as in heavy traffic.
■Charging the battery
The electricity stored in the battery will dis-
charge gradually even when the vehicle is
not in use, due to natural discharge and the
draining effects of certain electrical appli-
ances. If the vehicle is left for a long time,
the battery may discharge, and the engine
may be unable to start. (The battery
recharges automatically during driving.)
■When recharging or replacing the bat-
tery
●In some cases, it may not be possible to
unlock the doors using the smart access
system with push-button start when the
battery is discharged. Use the wireless
remote control or the mechanical key to
lock or unlock the doors.
●The engine may not start on the first
attempt after the battery has recharged
but will start normally after the second
attempt. This is not a malfunction.
●The engine switch mode is memorized by
the vehicle. When the battery is recon-
nected, the system will return to the
mode it was in before the battery was dis-
charged. Before di sconnecting the bat-
tery, turn the engine switch off.
If you are unsure what mode the engine
switch was in befo re the battery dis-
charged, be especially careful when
reconnecting the battery.
WARNING
■Avoiding battery fires or explosions
Observe the following precautions to
prevent accidentally igniting the flamma-
ble gas that may be emitted from the bat-
tery:
●Make sure each jumper cable is con-
nected to the correct terminal and that
it is not unintentionally in contact with
any other than the intended terminal.
●Do not allow the other end of the
jumper cable connected to the “+” ter-
minal to come into contact with any
other parts or meta l surfaces in the
area, such as brackets or unpainted
metal.
●Do not allow the + and - clamps of the
jumper cables to come into contact
with each other.
●Do not smoke, use matches, cigarette
lighters or allow open flame near the
battery.
■Battery precautions
The battery contains poisonous and cor-
rosive acidic electrol yte, while related
parts contain lead and lead compounds.
Observe the following precautions when
handling the battery:
●When working with the battery, always
wear safety glasses and take care not
to allow any battery fluids (acid) to
come into contact with skin, clothing
or the vehicle body.
●Do not lean over the battery.
●In the event that battery fluid comes
into contact with the skin or eyes,
immediately wash the affected area
with water and seek medical attention.
Place a wet sponge or cloth over the
affected area until medical attention
can be received.
●Always wash your ha nds after handling
the battery support, terminals, and
other battery-related parts.

3227-2. Steps to take in an emergency
1Stop the vehicle in a safe place and
turn off the air conditioning system,
and then stop the engine.
2 If you see steam:
Carefully lift the hood after the
steam subsides.
If you do not see steam:
Carefully lift the hood.
3 After the engine has cooled down
sufficiently, inspect the hoses and
radiator core (radiator) for any
leaks.
 RC350/RC300 AWD
WARNING
●Do not allow children near the battery.
NOTICE
■When handling jumper cables
When connecting the jumper cables,
ensure that they do not become entan-
gled in the cooling fans or engine drive
belt.
If your vehicle overheats
The following may indicate that
your vehicle is overheating.
 The engine coolant temperature
gauge ( P.66) is in the red zone
or a loss of engine power is expe-
rienced. (For example, the vehicle
speed does not increase.)
 “Engine Coolant Temp High Stop
in a Safe Place See Owner’s
Manual” is shown on the
multi-information display.
 Steam comes out from under the
hood.
Correction procedures

3237-2. Steps to take in an emergency
7
When trouble arises
Radiator
Cooling fans
If a large amount of coolant leaks, immedi-
ately contact your Lexus dealer.
RC300
Radiator
Cooling fans
If a large amount of coolant leaks, immedi-
ately contact your Lexus dealer.
4 The coolant level is satisfactory if it
is between the full (“FULL” or “F”)
and low (“LOW” or “L”) lines on the
reservoir.
 Engine (RC350/RC300 AWD) Reservoir cap
“FULL” or “F”
“LOW” or “L”
 Engine (RC300)
Reservoir cap
“FULL” or “F”
“LOW” or “L”
 Intercooler (RC300)
Reservoir cap
“FULL” or “F”
“LOW” or “L”
A
B
A
B
A
B
C
A
B
C
A
B
C